Derivative Instruments - Notional Amounts Outstanding under Foreign Currency Contracts - Fair Value of Assets (Details) - Not Designated as Hedging Instrument - USD ($) $ in Thousands	Jun. 30, 2017	Sep. 30, 2016
Foreign Exchange Contract
Derivative [Line Items]
Fair Value of Assets	$ 102	$ 5
Foreign Currency Contract, Buy British Pound, Sell Norwegian Krone, Maturing July 2017
Derivative [Line Items]
Fair Value of Assets	2
Foreign Currency Contract, Buy United States Dollar, Sell Israeli Shekel, Maturing July 2017
Derivative [Line Items]
Fair Value of Assets	1
Foreign Currency Contract, Buy Euro Sell British Pound, Maturing July 2017
Derivative [Line Items]
Fair Value of Assets	$ 99
Foreign Currency Contract, Buy British Pound, Sell Swedish Krona, Maturing October 2016
Derivative [Line Items]
Fair Value of Assets		1
Foreign Currency Contract, Buy United States Dollar, Sell British Pound, Maturing October 2016
Derivative [Line Items]
Fair Value of Assets		2
Foreign Currency Contract, Buy Korean Won, Sell United States Dollar, Maturing October 2016
Derivative [Line Items]
Fair Value of Assets		1
Foreign Currency Contract, Buy United States Dollar, Sell Israeli Shekel, Maturing October 2016
Derivative [Line Items]
Fair Value of Assets		$ 1